초록(영문)
In mathematics, the theory itself is important, but submitting the solution of a problem in real life by using mathematical theory is also important. subway line number 9 (seoul metro 9) has a different feature from other lines' general and express trains: it runs on one line with bay-lines for the improvement of transport and to reduce the cost of construction. Because of seoul metro 9's operation plan, there is a delay time during rail time, so previous research tried to solve these problems, and many studies tried to make its operation more efficient. However, previous studies didn't use mathematical models to explain the improvement of the efficiency of the operation exactly. In this research, we made a mathematical model for subway operation through an indefinite equation and an equality and submitted a more efficient improvement plan. We expect our research will be used as a basis for determining a better subway operation plan for all-stop and express trains.